Signaling circuits for toll lines



J. DAVIDSON, 1R. SIGNALING CIRCUITS FOR TOLL LINES.

APPLICATION FILED DEC. 12, I918- Patented Apr. 25, 1922.

6 SHEETSSHEET l.

' D I N VEN TOR. J fiwmfswz, J1: BY

ATTORNEY I. DAVIDSON, IR. SIGNAL ING CIRCUITS FOR TOLL LINES.

APPLICATION FILED DEC-12,1918- Patented Apr. 25, 1922.

I I I I I I I I I I I I I I III-II I IIIIIIIIIIIIIIIII III IIIII m T m m all-II.

A TTORNEY .1. DAVIDSON, 1R. SIGNAUNG CIRCUITS FOR'TOLL LINES.

APPLICATION FILED DEC. 12. 1918.

1,413,708. Patented A r. 25,; 1922 6 SHEETS-SHEET 3.

.I. DAVIDSON,..IR- SIGNALING CIRCUITS'FOR TOLL LINES.

APPLICATION FILED DEC. I2| IBIB.

' ATTORNEY Patented Apr. 25, 1922.

e sums-sum 4.

I. DAVIDSON, In. SIGNALING CIRCUITS FOR TOLL LINES.

APPLICATION FILED DEC. I2, 1918.

rammed Apr. 25, 1922.

6 SHEETS-SHEET 5.

A TTORNEY .I. DAVIDSON, In. SIGNALING CIRCUITS FOR TOLL LINES. APPLICATION Him use. 12, 1918.

Patented Apr. 25, 1922.

6 SHEETS-SHEET 5.

I I N V EN TOE. Jfiawdw/l, (i: BY W- A TTORNEY Jomi mvmsoa, Jrafoi macaroni ire, nnwannsninssrenon PHONE AND TELEGRAPH oomrANY, A CORPORATION OF NEW Y RKL" j tance' connections: at signaling; a path: to ;-.be iised-for silpervisoryl and :other; signals neces sary in connection with the'establishment of such connections. E lnorderi to reduce-the expense involved in suchyan arrangement;

it has beerr proposed to-provide aeommon signaling Zpath (for a plu'ralitywof: line's and successively? connect isaid commonxpatl-i -W itli' local signaling 'circuits individual jto the linesat each end-"thereof by means of ia rotary distributor or equivalent device. Arf rangements of this character are disclosed in llnitedStatcs patentsto Bancroft Gherardi.: Numbers 1.251.363 and 1,251,364, granted December 25, 1917. 7

One of the objects'of the present invention is' to improve and simplify the apparatus and system'of the patents above referred to, although other and further objects of the inventionv will be apparent from the descrip tion hereinafter given; .1 A f These objects are accomplished-by usin; an intermittently operating distributor for sending code signals over the common path, each toll line having a definite set of code combinations individual thereto so that si 'rnals overa particular toll line will be transmitted by the code combination assigned to it.

her e a number of distinct signals must be transmitted over .each toll line, it will. in general. be necessary to assign to each line a code combination for each. signal to be transmitted. The invention further contemplates the use of the same code combination to transmit more than one signal over a given toll line. by :u'rangin; thereceiving and translating apparatus to differentiate between code combinations transmitted at SIGNALING CIRCUITS FQR T ULL LINES.

Specification of Letters Patent. Patented Apr; Application filed December 12,1918; Serial No. 266,486.

25 different stages of the establishment of the connection. a f S nce the intermittently ioperating distrib- -uto'r transmitsjbut one signal for eachoperation thereof, the invention contemplates the provision; of suitable means .for delaying the signals of aplurality of toll, lines which may be simultan'eouslyinsignaling condition, a's;wellf as meansfordetermining the r rns iqh h es gn l 'i a p u l y of line'srareto be ;transmitted.- .flfhese functions 81 2;3 Q .nPlh 5 ,;r3'5- her n: disc se y mea s nfse s of rql ysie ps t d it each 1ine,-said relays bein Jarranged so that when the relays correspon ing; to one toll-line are actuated. the. circuits of? the sets o v relay associated; with other lines are rendered inoperative; :Said sets of relays are also provided-with contacts-whereby the code combinations transmitted by the distributor willbe determined.

I In order to translate the transmitted code combinations into: suitable signals-for the proper toll line, theinvention contemplates the provision of areceiving apparatus which will respoll d to a particular combination to set into operation thesignal fora particular line and which is represented by that code combination. The receivingapparatus. is herein disclosed as a pyramid relay combination of a .type well known in the signaling art, but it will be understood that any suitable translating apparatus may be used for this purpose, v

Since the otranslating apparatus must be arranged to translate and transmit a large number of briefimpulses to the signaling apparatus, it is desirable that in certain instances some arrangement be provided for prolonging the impulses to maintain the signal for a definite period. The invention. therefore, contemplates the provision of means forsecuring thisresult. Said means. as disclosed, comprises a pair of locking relays responsive to the impulses and arranged to separahly maintain the impulses, the locking circuits of said relays being so controlled by an interrupter that at least one of the relays will always be maintained energized for a predetermined minimum period of time.

In long distance toll trunks repeaters are of the particular line with which the signal originated is rendered operative. In a similar manner,-the apparatus is arranged so' that the disconnect or other signal sent at the termination of a conversation may renderthe repeaters inoperative.

j Still another feature of the invention relates' to iiieans for transmitting ringing signals. *Where the toll trunks ar composited for telegraphic purposes the; transmisicm o'f ringing current over the toll trunk-inter fres with'the operation of --the"-l\fo'1se apparatus because of the low frequency of the fing'ingrnrrent. YIfn' accordance with certain aspectsof this invention, therefore, the apparatus may be so arranged that when it is desired to ring the called subscriber, the ringing-"key, instead of appl ing-winging current to the toll trunk will transmit a "special signal over the local sleeve conductor of the toll cord, which will be transmitted as'a special-code combination -over' the commonsignalihg path to operate ringing apparatus at the distant end' of the toll trunk, whereby the called line may he rung. The called party may, therefore, be signaled without interfering with the Norse apparatu's.

The invention may now be more fully nnderstood by reference to the following de scription. when read in connection with the accompanying drawings. Figures 1, 2, 3, 4 and 5 of which when placed end to end in regular order constitute a circuit diagram of one embodiment of, the invention; while Fig. 1. when substituted for Fig. l and taken with the remaining figures constitutes a circuit diagramof a modified form of? the invention.

Referring to the drawing, a toll line L is illustrated as extending between two stations. A. and C. said toll line being provided with a two way repeater R at an intermediate station l3. At the originating station the toll line terminates in the jack J, with which a plug i" of a toll cord T is adapted to cooperate. inc toll cord being used in establishing a cornzection between the calling sub.- scriber's line and the toll line. At station C the toll line L terminates in a plug P5 adapted to ecu-operate with the jack J" of :1

toll switching trunk T, whereby the toll line may be connected with a called subscribers line. It will be understood that while but one toll line is shown, any desired number ottoll lines may extend between stations A and C.

In order to provide for the transmission of supervisory and other signals necessary in connection with the establishment of a connection over any of the toll lines, a signaling path P extends from station A to station B, said path being common to a large number of toll lines. A similar ath 1? extends from station B to station The signaling paths P and P terminate at stations A and C, respectively, in bridged polar duplex sets of the type commonly used in telegraphic transmission, while at station B the two paths are interconnected. by means of a, duplex repeater set whichcon'sists essentially of two bridged polar duplex' sets. The duplex repeater set is provided in order that the filament circuit of the repeaters may be controlled in a manner hereinafter described. In installations where the repeaters are not used, the duplex-repeater set may be omitted and the paths P and P directly connected' Signals are transmitted fronistation A to the; path P by means of an intermittently operating distributor TD similar to the so called start-stop distributors used in printin'g telegraph Associated. withi-ea'ch toll trunk is a set of relays such as'K M K M and so forth. \Vhen a signal originates with a toll line such as L the corresponding relays K and M operate to perform the triple function of locking out the relays of other lines on which signals are originated at'the same time, of determining the order in which the si nals shall be transmitted, and of translating the signals into code combinations which are transferred to a set of storing relays 1 to 6. inclusive, for the purpose of storing the code combination until ithas been transmitted by the distributor. The code combinations transmitted over the path P are repeated at station B by means of the duplex repeater set and are then transmitted over the path I to station C. At station the code combinations are received by means of an intermittently operating receiving distributor RD, similar in character to the so called start-stop receiving distributors used in printing telegraph systems. In order to translate received (Ode combinations into suitable signals and to appropriate the signals to the proper line. a pyramid relay combination of a well known type is provided as indicated in Fig. 4.

In order to control the filament circuits of the repeaters, such :18 R of the various lines, line relays 12 and 13 are provided in the duplex repeater set to impress the reiyeia'pos peated code combinations upon receiving distributors FD and FD, located at the repeater .station. These receiving distributors are identical in character with the distributor RD, already described, and are associated with pyramid relay combinations similar to that shown in Fig. l. These pyramid relay combinations translate the received code combinations into signals for selectively operating filament control relays of the various repeaters. In the'arrangemcnt shown the distributor FD and the associated pyramid relay combination control the filament circuits of repeaters in lines which are used for connections originating at station A and extendin to station C. The receiving distributor. ated pyramid relay combination, on the other hand, is used for controlling repeaters of to'llilines which are used for connections completed in the opposite direction.

Fo r transmitting signals originating-at station 'Q, a sending'distributor TD" is provided'atsaid station and sets of relays, such ingan endless chain, ar e associa ted withitlie yarious tollilinesj forl'the same purpose, as manual-lean -d.eseibe -@a e ion with: station-A. In order to recei-y'e the 'signals transmitted fromf station C, a receiving distributor RD 'similar .to the distributor is proyidedat station A, and 'a'pyramid relay combination is associated ithe'r'ewith for the'purpose of-translating the received signals.

Further details of the structural embodiment disclosed will be clear from a description of the operation, which'is as follows:

Assuming that a call is originated at station A and is to be extended over the line L to the station C, the toll operator at station A inserts the plug P of the toll cord T into the jack J of the toll line L thereby connecting the calling subscriber to said toll line. By this operation a circuit is completed from battery, through the lamp 14, over the sleeve contacts of the plug and ack and through the winding of the relay 15 to ground. 'The relay-15 is energized over this circuit. but the lamp 1 does not glow when connected in series with the-relay 15. Relay 15 at its left hand front contact closes a circuit from ground over the upper back contacts of relays 16 and 17, over the back left hand contact of relay 18, through the winding of slow release relay 19 to battery. thereby energizing the relay 19. Relay 19 upon being energized holds open the initial energizing circuit of relays 16 and 17 to prevent their actuation.

The right hand armature of relay 1?, in passing from its back to its frontcontact, momentarily opens the circuit of a locking relay 20, which may be traced as follows: from ground, back right hand contact of re- -back contact of relay 27 to battery' 1 D and associ-- lay 15, winding of relay 20, upper. frontcontact of said relay,lower back contact of relay 21 to battery. Relay 20 is thereby deenergized and a circuit is closed from ground, over the front right hand contact of relay 15, lower back contact of relay 20. over conductor 23, through the winding of relay K left hand winding of relay M left hand back contact of relay M and thence in series over the right hand back contacts of the relays corresponding to K of other lines, and finally over the right hand back contact of relay K thence over the back left hand contact of relay M back left hand contact of relay 26 and thence over lthe he circuit above traced is only established in the instance that relays corresponding to K and M of some other line have not already been energized, as will be hereinafter pointed out." 4 Therelays K and M are energized-overthe circuit above described, andrrelay K at its' inne'r right hand contact closes-a locking circuit f rorn ground, j through the :windingof said relay; throughthe left hand; "winding and 'left hand front contact of relay and thence tobattery, at'the back cdntact of relayQ'L- fRelay M, at its right-handiront contact completes" a locking circuit -;rrdm ground-;-over the back right hand contact ofielayM front rightliand 'contact of relay M. and through the right handwinding'of said relay,-thence over the-back right-hand contact-of. succeeding relays 'of otherlines and finally'oyer the back right hand contact of relay M through the winding of relay 2G to battery. Relay 26 is thereby energized and at'its front contact opens the circuit previously traced, from battery over the back contact of relay 27. Battery from said point is now connected directly over the front left hand contact of relay M .The result of the circuits thus established is that for lines simultaneously originating signals, the line having relays nearest to the relays 'K and M and on the'right of said rclaysfwill have preference beginning with line L then line L line L,.;,,-and soforth. For, instance, suppose that signals were simultaneously originated on linesL and L \Vith the circuits in the condition above described, the relays of'line L will take preference, since the energizing circuit for the relays of line L will extend over the right hand contact of relay K which will be opened. Said circuits may be traced in pa rt as follows: through the winding of relay K left hand winding of re lay back left hand contact of said rclay, front contact of relay 26. back right hand contact of relays K and K and over the front left hand contact of relay M to battery over the back contact of relay 2?. Relays K, and .il however, may not be operated: until the relay K is restored to M remains locked up through its right hand winding and the windingof relay 26, after the relay K has been deenergized:.through the Winding of relay K left hand winding of relay M back-left hand contact of said relay, back right hand contact of relay K front left hand contact of relay M,and over the back contact of. relay 27-1110 battery. As soon as the relay H is energized'it is locked up over its right hand front contact. right hand-winding in series with the; winding of relay 26. The locking circuit of relay M, is at the sametime opened and the said-relay is deenergized; r,

The relays -M,,;M etc, maiy he considered as an endless chain so that-to one standing. within the chain and looking out, the relay M will be immediately to the right of relay M,, although. for convenience shown to. the left thereof. in the drawing; When thus con-, sidered,j it will begseen that each of the relays M M etc;, isf lo'ckefd; up whenener} gized and can only be unlocked. by a relay immediately to the-right thereof, as'viewed by aperson situated as above-described. It willalso be clear that as soon as such a relay i energizedand-unlocks the circuit a new order of precedence is established, begin: ning with the new relay locked up, which, in this case is relay M,. It will be noted that battery is now connected to the circuit from the back contact of relay 27. over the front left hand contact of relay 11,. As soon as the relay K is restored to normal a circuit through relays K and M, may be established over the back left hand contact of relay M front contact of relay 26, back right hand contact of relay K and left hand front contact of relay M to battery. The relay M when energized opens the locking circuits of any M relay which happens to be locked up to the right thereof, and; is in turn locked up through its right hand windin}; in series with the winding of relay. 26. It Krill be seen, then, that when the relays of any one line have been actuated and signals originate with a plurality of other lines simultaneously thereafter, that the line whose relays lie nearest on the right of the relays last signaling will take precedence in regular order.

Returning now to the signal which energized and locked up the relays K, and M a ('irruit is completed over the right hand front contact of relay K, as follows: from battery over the back contact of relay 27, front upper back contact and Winding ofrelay20 and front contactof relay lite; ground.

Relay 20 is thereby energizedv and isloclred up. over a circuit. from ground, front contact of relay 15, winding and upper contact of relay 20. and over. the back contac't off 1elay -.21 to battery. lielay K at its'innei' left hand front contact connects ground to conductor .29 of a series of. conductors con trolling the circuitsof the storing relays 1 to 6 inclusive. The K relays, of. the various linesare arranged to ground the conductors controlling the relays l to 5 in .various combinations, depending upon the line'iwhich is signaling. Each of the K relays is; also pro.- vided-with an additional contact; .viz.,-'its extreme hand, contact, whereby a spe cial ground is applied to conductor ,contr'ol ling relay, 6, thereby, giving an} additional code si-gnal for each'linej Beaming "new t relay-Ki; rc i is completed. r0r.. the.fr1a 5 fizjom ground; oye'r the inner left, hand: contact of relay K l f t sht ha d i 'intlingpf is et bat ery-i l e bther. r ays; fo' n 'l. o? 6 inclusive Zaire not; energized for this fp'art icular combination, but the relay 511s 'ener gizedover the circuitabove'jtraced' and' s e han a nt was comp et 1. 1 -i circuit through lefthand irin'ding; through the I Winding of relay 35sec. oyei the back contact of. relay 36 to groi'iiid. lay 35 is 'the'reby energized andcomplet'es grcircuit-from ground over the inner ring 3? brusir andsegznent 3S the jdistribit tor, front contact of relay 35, through the winding of the start-magnet 39 to battery. The brusharmofthe (listri'bi'i'tor is now rclcase d rotates over. thesegmcnts.

Inthe normal condition of the brusharni positive battery .is connected orer the seg ment 4*, brush and ring 40 to the signaling path 'P. As soon as the brusharm passes from segment 1' to segments negative battery is connected tothe signaling path thereby operating the polar relay e1 to open the circuit, traced from ground, over, the closed contact of the polar relay 41, through the windings of relays 12 and 4L2 in series to battery. Relays 12 and 42 are thereby deenergized and pole changing relay lljtherefore disconnects positive battery from path P and applies negative battery thereto. The polar relay 43 at station C, thereupon loves its armature to its lower contact and completes a circuit from ground, over said contact, over segment *5, brush and segment l6 of the distributor and tlurough the winding of start magnet 47 to battery, therehr releasing the brush-arm which begins to rotate over the segments of the rece' ing distributor RD. At the same time the relay 12 at station B releases its armature and it llO 35 3 12 and 42am energized, the latter transmitcircuit is completed from ground over the back contact of said relay, over segment 48,

brush and segment -19 of the distributor FD and through the winding of the start magnet 50 to battery. The 'brusharm of the distributor FD is thereby released and rotates polarity of which is controlled by the storing relays '1 to' G'inclusive. It will be recalled that relay 5 only was energized and, consequently, negative battery will be ap- "plied to all of the segments except se gment 5 which has'positi've battery applied thereto.

A code" combination will, therefore,v be

transmitted to the signaling path P, consisting of four negative impulses, one positive "impulse and another negative impulse. Ifhe circuitforfthe first negative impulse Willfbe as ifollows'zflfrom' negativebattery over the back right hand contact'of relay 1, segment 1 of the distributor, brush and ring 40 of and 42 are dee'n'e'rgi'zed,f the 'latterf-relay thereby "traii'sinitting a negative impulse 037919319 l 3th, 1) causing the polar relay 43 to "shift' its 'armature to its lower-"contact.

iNo'effect "is produced on the receivingdistributors FD and RD by the negative im-. pulses. As" soon a'sthe fifth and positive" impulse is transmitted, however, therelays this: a positive impulse over the path P,

' which causes the polar relay 43 to shift its armature to its upper contact. A circuit is thereby closed from ground, over the upper contact of polar relay 43. over the segment 50 of the distributor RD, brushand segment 55' of said distributor, through the winding of relay 55' to battery. Relay 55 is thereby energized and is locked up over its front right hand contact and the back contact of relay 51. At the same time the relay 12 at tracts its armature and completes a circuit from ground, over its 'front contact. seg- 'ment 52 of the receiving distributor FD, segment 555 and through the winding of relay 555 to battery. The latter relay is energized and locked up over its left hand front contact and the back contact of'relay.

The brusharm of the distributorTD now passes over the sixth segment, transmitting another negative impulse. and finally comes to rest on the positive segment 1-, thereby transmitting a final stopping impulse, which causes the relay 12 to hold open the starting circuit of the distributor FD and the relay 42 to transmit a positive impulse over the path P, whichin turn causes the polar relay $3 to hold open the starting circuit of the that saidrelays are ready to-store up the -.next signal,

through its middle winding, 'l0wer'-.:Eront receiving distributor RI). As the arm of: the transmitting distributon passes over segment 54:, :a, circuit 1 is completed from 36 to battery. Relay 36 opens the circuit of -relay"35 and the locking circuit-of anyiof the relays 1: to. 6, which'had been previously energized; restoring the same. to normal, so

In the meantime, the brusharm, as soon :as it passed from the starting segment s atrthe beginning of its rotation'closed a circuit from ground over inner ring,3i',.brush.and 8O segment56 of the distributor andthroughr: the winding of relay '27'to battery, f Relay 27 is thereby energized during; a portion of the travel of-thetbnishatm of the distributor and during said :pe'riodiholdsopen the, loclzing circuit of the. relay-;K,-Iwhich:'-(it ,becg remembered), was traced =through,\the- .left han'd Winding of relay M andIoventhe-iront left hand contact of said lrelayl Belay I I I "is thereforerest'oredto nornaaliso; that the ithe: distributoiWto the "path {P.' Foreach negative impuls'transmitted the relays-'12 signal of thenext line iniorder- ,may be trans-e, s

--lated and stored upon the stoning relaTys ,1 i to "ii-inclusive." zzu-izi mi, Y Returning" now to the greceiving'idist ibuitor :RD--at station C,it'will;be;remembered that in response tovthei-transmission, Qfftheve code combination l described the, -,relay right hand back contacts-of pyramid-relays 5f); 60. 6'1 and 62, thence-overconductor 63.

over the lower back contact of relay64=and= through the upper Win'din ofsaidrelayto ground. Relay 64 is there y energized and completes a locking circuit- :from; battery,

1 10 contact and upper winding to ground :':The 1 brusharm of the distributor DOW'PaSSGS-OVGI. segments 67 and 68 and-'comes'to-rest; thereby completing a circuit from ground: over said segments and through the-winding of relay 51. Relay 51 opens tllBlOCklIlgxClI-m cuit of relay 55 which' is thereby deenergized and the pyramid selecting *circuitis restored to normal.- 1 v 5 In the meantime the brusharm ofthe distribut r FD. which in response to'the trans mission of the code combination just described energized and locked up relay 5'55, has passed over the segment 69 and 70 thereby closing a momentary circuit from negative battery, over the right hand back contact of relay 666, 'over -the segments 69 and 70. over the front contact of'relay 555, over the contacts of pyramid "relays, similar to those shown in Fig. 4,

"overconductor 71; over thetaupper back "contact (if-relay 72 and-through the-lower winding oi-saidrclay'to ground. Relay .72

is thereby energized and closes a locking circuit from battery, through its middle winding', upperfront contact and lower winding to ground:- At its lower front contact relay 72 completes the filament circuit of the repeater 'so'that the repeater is now ren- 1 (lered operative for transmission -over. the

line L Coming back tot-he relay (St-at station G,

which was energized and locked: up in response to thecode'comhination previously described, said 'rela'y'jat its. ufiper tront oontact c'o'mpletes'ecircuit -for the relagw 173 which. per *E-rbntcbnupon heing energized eti its= u "tact firepares the circuit of-4:- ie'left winding relay Z4 and etitsiniddle ifi'ont cont-wet bom- 201mg a. circuit'fromiground. over the lower 1 'c k eotitact'fif relay 75 and through-the I gaure' igm '76 m batter =The gunrd im 2-76 is fidw c'amhed to=glow thereby k T' over which the conneetmnumify be 9 i =e'xtndedtq th line I'of the'caliedssidis'driber. 3 This operation completes eircnitl oifithe sleeve =reliy 77; where-epon- 'a circuit isebom- "jpleted forthe-kelaj'fii'); whiehuupon being energized "front contact and atuits lower contact aopens the cn'cuit'of the-guard'lamp iii-whichis now eXting'uis h'edj 1 Y 1 Relay 7 7 at itsfront contact nls'o completzss a circuit from ground over ciondu'ctorfi 8. back right hand contacts of relays 79 and 80. ovcr- 0 conductor 81, over the lft-hand-laaeli contact- "or' relay 74, upper back-contact of relay '89. over conductor-82 and through the Ewindi n9; of relay K right hand winding of'relay. 2M right hand back contact of reln-yfi-Mi and thence in series-over theback lefthand um 'tacts of other K relays-over tlreuback-right hand contactof relay M back contact, oi relay 85 and over the back contactof rel'ay 86-116 battery. RelaysK- and M 'upon he-' ing energized operate to lock out sii'nilur relej's 'of other 'lines 'and to determine the order of preference of other lines upon which; signals may simultaneously arise. Belay K it its lei-t hand front contactcompletes a cir cuitfrom battery. over the back contact of relay 86. front right hand contact (ii-relay M ,'front left hand c ntact of relay li .0011- du'ct'o'r 83. lowerlmck contact and windingef relay 89. back right hand contact of relay 6 7'; andthence over circuit previously traced to ground. Relay 89 is now energized and is locked up over its lower front contact.- thereby opening the initial energizing circuit of the relays K and 11., which. however, re- 65 main locked up.

.-ing of relay 4 indibeting .3 the: 'elagy' 94 f t?) the toll operatofi zitrstation'fif:that: the istoring:ielay,s 5f; nd 6f,

tor has to thegtbll int-us; perzitor thereupon insettszthe etoaopeuz plug 1?, into the jack J of the tcllbwitohing which -i !re Sf0,td l0, 1Qmfi;l.!

. Relay K at its inner righthand front con- =tact connects ground to conductor 88 wherebgrthe relay 5 is energized through its left hand winding. .At the outer right. hand front contact of relay. K "a circuit is closed from ground over the front contact of relay -73. back contacts of relays wand 80, over the conductor 93, right hand-front contactol? relay; K f. conductor 87 left haud \vindingof r'ela s 6 to batter v.. Relays 5 and}? are energized-and locked up over their. right hand frontcontacts-inseries with the-Wind- 9L= Relay 94: upon being encrgized. closes the circuit otthe starhmugnet 95. whereby the brusharinpfjthe' distributor EDD-His released tetrensmit anegatite starting-impulse ifollbwed by a code combination consisting: pfiiogr negative i mpulses and ,two positive. After transmitting. the:

.impulses; \co'de oombina i nztl ebru h rm amp e th nireuic ofirelafv-fifi remseg nenwlan il i ring 98. whenebyfrela'y flfi opens thelcimgcuitj of fanclihmkpld l sfi ll fii t -ixll resarms th l ve-.1- to nor ate-i elem-fi isieleqj rs te heil ckinerirqu mfthe $1 3 9 utt r n ati imin :i rn ectu es- 1-$ ni Pe e a g n eehy-SQgt-statipri, llelav ldre ,the 95 l t sh me h s is ibiiteeF f fin -m nt l r-tmt e z ke y de m'i ei tifli ence to :distributorgflnuand hru'sha'rm rotates EOYGI. the, reeeiyingsegm entsi of the I -distributor.;. the same time tlie iiolc changing relay 99. transmits a ncgatirc iniipulseover the path 12,:whi chin turn actuutcs th'epolar relay 100 to actuate the start mag- -nct 101'of the digributor 1H1 thereby release H'Eh rail on of ing the brusharin of said distrihutor in @1 05 -mzumeusrmtlar to that already lescriiwd .withreference .to distril'mtor 11D. {l'he brushann of'the distributor RD rotates or'cr the reccixting segments 11. 22. and s1: forth. .but asthe negatirc impulsesoi thcreelcuui- 11 vbinationtransmit-ted are ineil'a'ti e-onlx rel.a ys.55 and 6.6.,areenergized and luckfll up in response to the last hrqpositive im pill-501% nf the codecombination. As the brush arm of. the distributorRDpasscs over segmentsg l-end. 102, acia'cuit-is om pleted fror'n' pee fiw. battery. segments MIL-and 101, front right hand contact of relay over the back left hand contacts of pyramid relays 103. lt l,

105 and 106 and thence over cuxnluclor WY. back right hand contact of relay 9' nml through the left handwinding of sa d relay ,to ground. Relay 1S is-energizcd by the positive impulse thus transmitted and completes a locking-circuit from battery. through its midcllega'inding and over its right hand. front contact and left-hand windin to ground. The positive impulse transmitted orvr conductor 107 persists long enough -o that it now passes over the front right hand contact- .130

1-0 cult in response to the code combination just an of relay 1S and through its right hand differential winding to ground. The relay 18 is at once deencrgized so that the code combination transmitted in response to inserting the plug P into the inch? is nefi'ectire to produce any signal at the originating station ,A. The pyramid relays associated with the distributor FD at station E are arrangei us to be ineffective to rinse an signaling cirtransniitted. In factthe pyramid relays are so arranged that no circuits-are completed for code combinations transmitted from the distant end of any toll line to the originating end thereof.

After the plug I; has been inserted in the jack '.l. the B operator completes the connection over the toll switching trunk T to the called subscriber. The receiver of the tc'ry over conductor 83 to again lock up rela i fifln By applying ground to the conductor $8, the relay K energizes and locks up the storing relay 5.

Relay 5. upon being energized is locked p and sets he distributor TD into operation to transmit a negative starting impulse followed hr a code combination consisting 'Ffonr negatire impulses, a positive and an Jitional. negative impulse. The combina tionlthns transmitted does not close any filament control circuit at the station B. At station A, however, the receiving distributor 11D is set into operation and energizes relay in response to the positive impulse so that when the. brush arm of the distributor 'passes'oi er seginentslfll and; 102 a circuit is'eloseG from negatire-battery over said segments, over the frontcontact of relay 55 N Called Subscribe! b ing 0111 hi's'switeh hook, -fa nil "t11e left'hand back contacts of-relays ground o'ver t-h front' contact of any 77,

:.ove1 the inner, front Contact of relay 7% upthe toll switching trunk operates in a 'manes e known in r t r dge b t y across its toll 'ng conductors, whereby the lien ma ru bi -relay arisjargized. B arper 'lfa'ck tantra of 'relayf89; overlthe ductoi' .82, throngliitll'elwinding of relay 1;, and righthand winding of relay'MJft bat- ,energiiod.

Cl1'C1l1t lS completed, atthe same time,

.from groimd; over the front contact of rethatonc of these locking circuits will -al-; rars be maintained closed. after the other has been opened for a period equal to the A: right haild frontcontact of relay 74=, rmnlui-Lor 108 and through the right 7 hand winding of relays 79 and 80 in parallel. Relays 79 and 80 are energized and at their left hand front contacts complete locking -ir:uits through their left hancl windings i and over the brushes of an interrupter 109 to ground. The brushes of interrupter 109 are so arranged with respect to the segments time that it takes for one of the brushes to pass over one-half of a segment of the interrupter. The speed of the interrupter may he so regulated as to mahe this period as long as desired, so long as one or the other o the relays T9 and 3 are maintained locked up. 4

Ground from the front contact of: relay IT and over the conductor 78 is disconnected by means of the relays 79 and 80, from the wires 81 and so that relay K when energized functions to connect ground to the conductor 88 only and no ground is con nected to the conductor 87 as in the case 'imisl) destriberl. Relay K when encras previously ilescribi-n'l connects batcO'nrelay 15 as. relay" 18" ai1d left vinding of sajid relay to ground,

hand contact of relay,*overthe 'up'per hack contacts of relaysflfiand 17, over-the te r- R ay K2 dj M1 e fier y-j 'i'rgmt left hand contact of relay 18 -and through the rcsis tancejilfi. ",This decreases th resistanre o f the'sl@i'e"circuits"snfli- -:-i entl v to'cansc the. lamp 14 to glojv thereby indicating to the. toll 'op'erato'r'atstation A. that the connection'has been completed to the called subscriber and that ringing cn r-' rent should now be applied. 'The operator thereupon transmits ringing currentfrom the toll cord over the talking conductors of the ping P and the 'jack I; to the ringing responsive rela 2!. The lorlz'ing circuit of relay 20 is thereby opened and'a circuit is complete from ground over the front right han contact otrclay' 15, lower back contact of :"ela 3 over conductor .23 and through the inding of relay K and the left hand winding of relay M to battery at the back rontaet m? relay 97.

lelav i nun functions to onnect battery from the lm-rl: contact of' relay 2-7. over its front right. hand contact. over conductor 24, vr-cer the upper hacl; contact and through the winding of rela 20 to ground at the front contact of relay 15,-thereby again energizinz: and locking up the relay 20. At its in nor lcit hand contactrelay K connects g onnd'weer the conductor 29 and through the. right-ligand winding of relay 5 to battery. Vela is acc rdingly energized and locked the ransmitting distributor to lurlrtunted to transmit a negative startingimpulse followed by a code combination of four negative impulses, one positive and one additional negative impulse. It will be noted that the code combination, fas transmitted. is the same combination as had been previously transmitted to actuate the guard lamp .76. v

The transmission of this code combination over the signaling path P causes the receiving distributor FD at station B to be actuated to close the circuit of relay 555, so that a'circuit is again completed from negative battery, over the back contact of relay 666, over segments 69 and 70, front contact of relay 5 55, over the contacts ofthe yramid selecting relays to conductor 71 and thence" over the upperfront contact of relay 72 to the upper winding of said relay to ground.

. Thecurrent flowing through this winding is in such a direction that the effect is cumula- 'tivewith respect to the other windings of the; relay and,consequently, no, useful effect is producedby this. code combinationat station B at this time.

i The. starting impulse and icombina- 1:

tion are also repe'ated by .meaus of the duplex-repeatingset to'the signaling path P 1-andat station G- operateto release the receivingdistributor RD' which functions as before toenerg ize the relay '55 in response to the positive impulse, so that just before the -;-brush arm comes :to rest a circuit is closed from-negative battery, over the back left Y hand-contact of relay 66'. over segments 57 and 58. over the front .left hand contact of relay 55' and the back right hand contacts of pyramid relays 59, 60, 61 and 62 to conductor 63 andthence over-the lower front contact of relay 64: and through the winding of relay 112 to ground. Current also flows in parallel with the windings of relay 112,

through the lower winding of relay 64, but this current isv in such direction that the effeet is cumulative with respect to the other two windings of'- the relay 6 1. so that, the relay is not deenergizedbut remains locked up.

Relay v112- closes a circuit from ground over its front contact and over the middle front contact of relay 75, in parallel through the windings of relay 113 and 11 1 and thence over the lower front contact of relay 73 to battery. Relays 113 and 114 over their right hand front contacts complete locking cireuits through their .right hand windings,

over the brushes of the interrupter 109 to ground. Said relays also complete a circuit over their left hand front contacts from battery. over the lower front contact of relay 73, left hand front contacts of relays 113 and 114: in parallel and thence through the winding of ringing relay 115 and through the right hand winding of relay 74 to ground. This circuit is maintained closed for a period determined by the action of the fi eetisba terr interrupter 109 in a manner already described in connection with relays 7 9 and 80. Consequently, relay 115 applies ringing current to the called line for a predetermined I period and relay 74 is maintained energized through its right hand winding during the from ground, over the front, contact of revl y 77., overfconductor 7 8, over the right hand back contacts of relays???) and 80, over l 7 ,41 1 pa b ki en a t 'felay 8 minister ge y K2 th i ght. In r filn l ay e i K i ronl in nv H I from e back contact ojfgrelay isetwert i saifi @18 or ithdi or r' meat hr hehitHen n e e i e r.the. ba kflfihai d i a tle re y vOfv 1,' l ht conductolfffil, back right hand con was i of relays :80- and .19, over 'conductor 78 and mat; q nrtt" 6f relay 77. a, ro nd.

Relay "8 9 is thereby again energized and locked up. Relay at its inner right hand contact connects ground to conductor 88, thereby energizing and locking up the relay '5'.' At its outer 'righthand front contact relay completes a circuit from ground,

over the front contact ofrelay77, conductor 78. back right hand contacts of relays "79 and 80, over conductor 93, front-right hand contact of relay K conductor 87 and vl'eftfhand winding of relay 6." to ground.

Relay 6 is therefore also energized and locked upi These relays uponf'closing their locking circuits actuaterelay t to set the transmitting distributor :TD'into operation, thereby transmitting a negative starting impulse followed by a code combination of four negative impulses and two positive impulses. This combination upon being transmitted over the signaling path P produces no useful effect at station but upon being repeated by the duplex repeater set to the path P, the receiving distributor RD at station A is set into. operation and locks up relays 55 and 66 in response to the two positive irn pulses. A circuit is thereby completed from positive battery, over the front right had contact of relay 66 over segments 101 and 102, over the front right hand contact of relay 55, over the back left hand contacts of pyramid relays 103, 104, 105

e'ft and contact c'on-' and 106 over conductor 107, over the right hand front contact of relay 18'and-through the-right hand differential; winding of said relay to ground. The impulse thus transmitted is of such adirection that the effecton the right hand windings of said relay is difi erential with respect to the other two windings, so that relay 18 is deenergized and at its left hand contact opens the shunt through resistance 110. so that lamp id is extinguished thereby, indicating to the toll operator that the called subscriber has answered.

Should the called subscriber desire to at- 'tract the attention of the operator at station A by flashing his'switch hook the operation of the switch hook will intermittently con nect battery to the toll switching trunk, thereby intermittently energizing therelay 74. Each time the relay 74 isenergized, the

' locking circuit of the relay 89 will be m0- m'entarily interrupted by' the movemen't of theleft hand armature ot relay'fd from one contact to the other. {A cir''cuit w ill, therefore; be completed "from ground om the front contact of relay177, over the front left hand contact ot 'relay f l and over the aippei back contactfof relay 89 to energize the relays; K and M5 I? A circuit will at the' sa'm'e time be completed -"from'jground overithe front contactof relay 77; over the'extreme right hand frdnthntact-ot relay 74, over conductor" 108 and-through the right-hand windings of relays'79 and 80 in parallel to battery, "Be1a'ys'79 and SOare thereby ener-j gized'and locked up over the brushes of the interrupter 109, as before described, to pre vents circuit being completed over conductor 78 to conductor 93.

--R elay K upon being energized, therefore, applies ground over its inner right hand contact to the conductor 88 to energize and lock up the relay 5. Relay 5upo'n being locked up sets the transmitting distributor TD into operation to transmit a negatire. starting impulse followed by a code combination of four negative impulses, a positive and an additional negative impulse. This operation isrepeated for subsequent energizations of the relay 7 1, whenever the line L obtains control otthe distributor. Consequently, a succession of code combinations. of the character just dcscribecl, will be transmitted over the signaling path P, so 1011;! as the subscriber manipulates the switch hook. The transmission of these code combinations produces no useful effect at station B. Upon being repeated to the signalin; path P. however, the first combination transmitted releases the receiving distributor RD and locks up the relay 55 in response to the positive impulse, thereby completing: a, circuit, as before described. from negative battery. through the pyramid selecting relays to conductor 10? and over the back right hand contact of relay 18 and through the lefthandwinding ofsaid-relayto ground Relay 18 isthereby energized and locked up as betoredescribed; The next code combination received again -locks up the relay 55 and connects negative battery through the pyramid relays to conductor 107 so that a negative impulse 'is-transmitted over said conductor 107, through the front right hand contact ofrelay 18, throughthe winding of relay 116 to ground. .2;

Relay 116 upon being energized'completesa circuit from-ground over itsfront contact, back contact of slow release relay 19-and thence in parallel through the upper windings of relays 16 and 17130 battery. Relays 16 and 17 are'then locked rip-through their lower windings andover the brushes of an interrupter 117 to ground. The interrupter 117 functions in a manner similar to that already described in connection .withthe infront-contact of; relays16zon-l7 andathence over: the front :left: handcontact 0fre1ayw18, through the resistance 1:10 to shunt: thewind= ing of relay 15. The lamp let-is thereby caused to flash intermittently-,i indicating .toetheop eratorxthat thecalled subscribenisflashing his switch-hook. 1' Returning now to the completion or the connection from the toll line -L. .;'to-the-tol1 switching trunk T. by the toll-operator. in

case-the. B operator hadfoundthe. called subscribers line busy she wouldhave plugged the toll switching trunk T.'. into the :jack of a busy back circuit. th'erebyintermittently opening and closing the toll switching trunk circuitto intermittently connect batteryacross thetoll switching trunk in' a manner similar to that described-inconnection with the flashing of the subscribers switch hook. This would cause the relay. 7e to be inter.-

mittently energized, thereby transmitting signals ot-the character just'described in connection with the flashing of the called subscribers switch hook. The relay s18 and 116- would be energized and the circuit through busy back interrupter 118' again completed to cause the flashing of the lamp 14. p The flashing of the lamp would, in this instance, occur before'the ringing signal had been received so that the operator would understand that the signal-indicated a busy condition of the called subscribers line.

Upon receiving a disconnect signal from the calling subscriber the toll operator at station A. would withdraw the plug P from the jack J thereby deenergizing the relay 15. Tlf right hand armature of the relay 15. in passing from front to back contact, momentarily opens the circuit of locking relay 20 which is deenergized and closes a lavs and 66 at station C.

circuit over back right hand contact of relaylzi, lower back contact of relay 20,- over conductor 23, through the winding of relay K. and the left hand winding of relay M to battery at the back contact of relay27. Relay K upon being energized connects battery from the back contact of relay 27, over its extreme right hand front contact, over conductor 24 and over the upper back contact and winding of relay 20 to ground over the back contact of relay '15. Relay 20 is again energized and locked up. Relay K at its inner front contact connects ground to conductor 29' to energize and lock up the relay 5. At its outervfront contact relay K closesa circuit from ground over the back contaet of relay 15, over conductor 25, left hand front contact of relay- K conl ductor 28 and th'rough the right hand windof 6 to battery. Relay 6 is thereby energized and locked up.

Relays 5 and 6 upon being locked the-relay 35 to; release the transmitting distributbr TD, which now iiunctio'ns, to

transmit a negative starting impulse followed by a code combination consisting of fbur negative. impulses and=two positiveinipulses. Thetrarismission of thisco'de com-' bignatibn over signalingpath P results in the'actiiation of relays-555 and 666 at station B. As the brush arm of the receiving distributoriFD passes over segments 69 and a circuit is closed from positive-battery,

over the right hand contact of relay 666. 35

over segments 69 and 70. over the front contact of relay 555, over the contacts 'of the. pyramid relays, over the upper front contact of relay '72 and through the upper diiferential' winding of said relay to ground.

The positive impulse transmitted through this winding is of vsuch a direction as to cause the relay 72 to be deenergized, thereby opening the filament controlling circuit of the repeater R The code combination just described, upon being repeated by theduplex repeater set, to the signaling path P, results in the actuation of the distributor RD tolock up rea A circuit is thereby closed from positive battery, over the front left hand contact of relay 66'. over segments 57 and 58, over the lefthand front contact of relay 55'. over the right hand back contacts of pyramid relays 59. 60. 61 and 62, over the conductor 63 and over the lower front contact and lower winding of relay 64 to ground. The impulse thus received is of such a direction as to deenergize the relay 64. which is now restored to normal. thereby opening the circuit of relay 73. Relay 73 closes circuit tom ground. over the back contact of its middle armature. over the lower front contact of relay 75 through the lamp 76 to battery. The lamp now glows indicating to the toll operator at station C that connection should be taken down. The operator thereupon withdraws the plug P from the jack J deenergizing the relay 77, which, in turn, opens a circuit of the relay 75, thereby extinguishing the lamp 76 and restoring the apparatus to normal.

A slight modification of the circuit at station A is illustrated in F lg 1 whereby the ringing signal may be transmitted without applying ringing current to the toll line. lVhere the toll line is composited for telegraphic purposes the low frequency of the ringing current which is applied to the relay 15, as in the circuit ,otFig. 1. The

relay 120 is marginal and is only operated when the potential of the sleeve circuit is increased, I as hereinarfter described. A specialform. of cord circuit isprovided for completing connections from the toll switching trunk (not shown) to thetoll line such as L Thisicord circuit terminates in plugs P and P, the plug P being adapted to cooperate with the acks of toll lines while the plug P is ada ted to co-operate with jacks of toll switching trunks. Relays 121 and 122 are included in the sleeve circuit of the cord, the former operating to close the talking conductors and the latter functioning to control the signal lamp 14.. A ringing key 123 is also rovided, said ringing key being arrange to connect direct battery potential to the sleeve circuit, thereby operating the marginal relay 120 associated with the sleeve circuit of the toll line to transmit the ringing signal.

Further details of the apparatus will now be clear froma description of the operation. which is as follows:

Upon connecting a calling line to the toll line L by inserting the plug P in the jack J. a circuit is completed from battery through the winding of relay 122, lower winding of relay 121, sleeve contacts of the plug and jack and through the lower windings of relays 119 and 1.20 in series 'to ground. Relays 119 and 121 are energized over the circuit thus traced, but relays 120 and 122 are marginal and are not actuated at this time. Relay 119 upon being energized, at its lower armature momentarily inc 'tional negative impulse.

As soon as the connection has been completed to the called subscriber, the called subscribers receiver being still upon his switch hook, a ringing signal is transmitted from station C to-station A consisting of a "code combination of four negative 1mpulses, apositive impulseand an additional negative impulse. This combination upon being received by the'distributor RD causes the relay -55 t'oEbe 'lockedup and 'a negativeimpulse is thereby applied to'the conductor' 107, which impulse 4 goes over the backright "hand contact of relay 1 18. and

through its left: h and 1 Winding --to ground,

.the'rebv energizizig and locking. up ithea relay 18. he energitation of relay 18clos'essa shunt oircuit about "the lower Awindings 2 of relay 119 and l20i from: :groundaover 5 the upper fron't contact of relay 5 '1'19, .over the upper back contacts- 0f" relays: 16' iand -17, overthe fiont lefthand contact ofrelay 18 and through the low: resistance upper windingsof relays 120 and 119'. The resistance of the-sleeve circuit is thereby decreased so that the 'marginal' relay "122 ;is'- actuated to close the' circuit ofthe lamp. 14;- which indicates to=the operator that the called subscriber should be rung.

The operatorthereupon actuates the ringing key 123 which over its lower 'front contact connects battery directly to the sleeve contact of the plug P, thereby short circuitin'g relays 121 and 122. Relay 121 is maintained energized, however, over a circuit through its upper winding and the upper contact "of the ringing key 123. Upon applying battery directly to'the sleeve contactof theplug P relay 120 is energized thereby opening at its lower contact the locking circuit 0115111 1 20, which is deenergized as before. As soon as the ringing key 123 is restored. the relay 120 is again deenergized and a circuit is completed from ground over the lower back contact of relay '12), lower front contact of relay 119, lower back contact of relay 20. over conductor 23 to energize relays K and M The energi- "zation of these relays causes the transmitting. distributor TD to transmit the same code combination as before: viz, four negative impulses, one positive and an addi- The transmission of this code combination causes ringingcurrent to be applied to the called subscribers line, in the manner already described. The remaining features of the operation are identical with those described in connection with the: first modification and need not be further discussed.

- The operations above described with reference to the two modifications of .the invention herein-disclosed, are characteristic of those taking place in the course of the establishment of a connection over any one of the tolllines of a group employing the same common signaling path. The .only essential diiterence in operation, so far as the establishment of connections over the. different lines is concerned, resides in the fact that different code combinations are employed for the transmission of signals in connection. with the various lines and While the invention is not limited-to the employment of any particulararrangement of= code signals.-- the; code combinations shown 2 in the followiiig. =table have been lfound tohe quite satisfactory; where 1 a group of. thirtytwo..-toll.-l1nes employrthe same; commo 51g nahngapaths 1; 1 1 i 1;. 3 v$. g als{111111,- t oiug Si alsiromducqrgk, tpin'coming arid. in g to ou't' fend. :1 1 Flash v p in".

1'... 0 2, ,1 5. 5 3. 1 v 4 -4 4. as ;1 a 341 a 5. 2 p 2s 2 52 a. 45 w '45 45s 45 45 7. .35 35 356 35s 55 8 25 :25 256 '25" 256 25 9. 5 .34- 134 346; 234 .34 10 24 24 246 24 245' .24 11.. 23 23 236 23c -=23 12... -345 .345 34511 I 345 3456 245 13" 245 -245 2456 245 2456 245 14 .235 235 12356- 235 2356 235 15 234 234 2346 234 2346 234 16.; 2345 2345 '23456 2345 23455 2345 17. 1 j l l6 1 16 l 18.. 15 15 156 15 15s 15 19. 14 4 14 45 .14 145 .14 20.. 13 13 136 '13 135 '13 21. 12. 12 l .126 12 126 12 22 145 145 456 145 1456 145 23 1:45 135 1356 '--135 1356- 24 125 .1125. .1256. 125 -1256 125 25... 134- .134- 1346 1:44 5 134s 134 25.. 124. 124 .1246 124 1245 124 27 v .123 123 1236 123 1233 123 23 v 1345 5 1345 13456 1345 1345s 1345 29 1 1245 1245 12456 1245 12455 245 30 12:15 1235 1235s 1235 1215s 1235 31 1 1214 .12346 1234 1234s 1234 32 12345 12345 123456 12345 123456 12145 7 In the above table, the numbers the first column indicatet-he numbers assigned to the .toll lines, While the numbers in the remaining rolumns indicate the order 01 the positi ve impulses in each group 01" six. The number 0 appearing, opposite the line in the second,third,fiftl121nd seventh columns of the table means that no positive impulses are transmitted. In other Words, a code combination, in this case, consistsof six negative impulses. In this connection, it will be noted, that in the drawing, Figs. 1, 1=

It will be obvious that the general principles herein disclosed may be embodied in many other organizations widely difl'erent from those illustrated without departing from the spirit of the-invention as defined in the=foilowing claims.

-What is claimed is 1i Ina signaling system, atransmission circuitextending-between two stations, a

- signaling path :extending between :said stat1ons,=me'ans responsive'to a change in the condition" of said"transmission circuit to transmit a code combination over said signa ling p'ath', means-responsive to a different change in the condition of said taiansmission circuit to transmit the same code combination'oyer saidsignaglin path, and means to translate the received code combination into two different signals individual to said transmission circuit. 1 v I 2. In a signaling system, a plurality of transmission circuits extending between two stations, a signalingpath common to said circuits and extending between said stations, means responsive to a change in the condition of any one of said transmission circuitsto transmit a code combination characteristic of said path over said signaling circuit, means responsive to a different change in the condition of the same circuit :to transmit thesame codecombination over said path, and means to translate the code combination characterist c of any line into two different signals individual to that line.

sion circuit at one of said stations for originating a plurality of signals of different types, means responsive to the origination of said signals for transmitting the same code combination over said signaling path to the other station,'and means at said other station to translate 'said code combination into a plurality of signals of different types for said transmission circuit under different conditions.

i. In a signaling systenna plurality of transmission circuits extending between two stations, a signaling path common to said transmission circuits and extending between said stations, means associated with each of said transmission circuits at one of said stations for originating a plurality of signals of; cliiierent; types foreach circuit, means;

responsive to the origination of said signals fortransmitting-the same code combination characteristicot' that particular circuit over the common signaling path to the other station, and means at said otherstation to translate the code combination characteristic of a particular transmission circuit into a plurality oi signals of-ditferengtypesforthat circuit under different conditions.

5, In a signaling system, a transmission circuitzextending between two stations and including :a normally inactive repeating apparatus, a signaling path extending between said stations,'nieans iesponsii'e to a change in the condition ot:said transmission circuit atone :stat-ionto transmit a signal over said signalingzqxith to the secondstation to actuate -.signaling.;apparatus thereat, means responsive f'to the it-rai smission' of said signal to lrender said repeating apparatus-active.

In a-. signaling system, a transmission circuit/extendingibetween two stations and including :a normally ';i nacti e I repeating ape paratns, aisigna'ling extending between said; stations,-;means raspomive to exchange inetheconditions nf said-transmission circuit'nt one-station to transmit a [signal over said --signafling-path :to: the second station 1 to actuatev signaling apparatus thereat, means responsive to the transmission of-said signal to render saidrepeating'apparatus active, means-zresponsive to another change in the condition of? said transmission :Zcircuit .to transmit another signal-over said'path to operate a signaliiignapparatus and means responsive to the transmission of the latter signal to render said active.

' 7; In a signaling'systei'n, :a pluralityof transmission circuitsexten'ding between two stations and each including normally inactive repeatingarrangements, a-signalingpath common to'said transmission circuitsand extending betweensaid stations, means responsive to changes in the condition of a repeating apparatus in- .plurality of said transmission circuits to transmit signals over said common signaling path, and means -I8SPOI1S1V6 =to the-transmistion-of said signalsto renderzactive't-he re peating arrangements of the transmission circuit with-which the signals originated.

8. In a signaling system, a plurality of transmission circuits extendingbetween stations-and each including normally inactive repeating arrangements, a signaling pat-h common to said transmission circuits and extending between said stations. means responsive to changes in the condition of a plurality of said transmission circuits to transmit signals over said common signaling path, means responsive to the transmission of said signals to render active the repeating arrangements of the transmission circuits with which the signals originated, means responsire to other changes in the condition of said circuits to transmit other signals over said common signaling path, and means responsive to the transmission of the latter signals to render said repeating arrangements again inactive.

9. In a signaling system, a transmission circuit extending between two stations and including a repeating apparatus, a signaling path extending between said stations, means associated with said transmission circuit at one of said stations "for originating a signal, means responsive to the origination of said signal to transmit a code combination over said signaling path, and means responsive to the transmission of the code combination to control the action of said repeating arrangements.

10. In a signaling system, a plurality of transmission circuits extending between two stations and each including repeating arrangements, a signaling path common to said transmission circuits and extending between said stations, means associated wit-beach of said circuits at one of said stations for originating signals, means responsive to the origination of signals at a plurality of said circuits for successively transmitting code combinations characteristic. of the circuits with which the signals originated, and means responsive to the transmission of said code combinations for controlling the correspond ing repeating arrangements.

11. In a signaling system, a transmission circuit extending betwen stations, a link circuit at one of said stations for establishing connections over said transmission circuit, said link circuit having tip, ring, and sleeve conductors, a signaling path extending between said stations, means associated with said link circuit for transmitting a special signal over said sleeve conductor a-nd'said signaling path to the second station and means responsive to the transmission of said signal for applying ringing current to a portion of said transmission circuit at said second station.

12. In a signaling system. a transmission circuit extending between stations, a link circuit at one of said stations for establishing connections over said transmission circuit, said link circuit having tip, ring and sleeve conductors, a signaling path extending between said stations, means associated with said link circuit for transmitting a special signal over said sleeve conductors, means responsive to the transmission of said signal for transmitting a code combination over said signaling path to the second station, means at said second station for connecting said transmission circuit to a called line, and means responsive to said code combination for ringing the called line.

13. In a signaling system, a plurality of transmission circuits extending between two stations, a signaling path common to said transmission cimuits and extending between said stations, means associated with each of said circuits at one of said stations for originating signals, a plurality of relays for determining the order in which said signals shall be transmitted and means for transmitting said signals over the common signaling path in the order determined by said relays.

14. In a signaling system, a plurality of transmission circuits extending between two stations, a signaling path common to said transmission circuit and extending between said stations, means associated with each of said circuits at one of said stations for originating signals, a plurality of relays for translating said signals into code combinations and for determining the order in which said code combinations shall be transmitted, and means for transmitting said code combinations over said common path in the order determined bysaid relays.

15. In a signaling system, means to transmit a signaling impulse, and means to prolong the etfect of said impulse comprising a plurality of relays responsive to said impulse, each relay being adapted to independently maintain the effect of said impulse, and means for maintaining one of said relays energized for a predetermined period after another of said relays has been (lB-GIIQI'Q'lZGd.

16. In a signaling system, means to transmit a signaling impulse, and means to prolong the effect of said impulse comprising a. plurality of relays responsive to said impulse, each relay being adapted to independently maintain the effect of said impulse, and locking circuits for said relays controlled by an interrupter, said interrupter functioning to open the locking circuit of one of said relays a predetermined interval after the locking circuit of another of said relays has been opened.

In testimony whereof, I have signed my name to this specification this 9th day of December 1918.

JOHN DAVIDSON, JR. 

